Cardiac prosthesis for helping improve operation of a heat valve

ABSTRACT

An apparatus ( 10 ) for helping improve operation of a heart valve includes a generally annular base ( 12 ) and a buttress ( 20 ) extending generally axially from and inwardly relative to an arc portion of the base ( 12 ). When the apparatus ( 10 ) is when implanted at an annulus of a heart valve, the buttress ( 20 ) thereof provides a surface with which a leaflet of the heart valve may move into and out of engagement for helping control blood flow relative to the apparatus ( 10 ) and heart valve.

TECHNICAL FIELD

[0001] The present invention relates to an implantable cardiacprosthesis and, more particularly, to a prosthesis that may be implantedat an annulus of a heart valve to help improve operation of a defectiveor damaged valve.

BACKGROUND

[0002] A heart valve may become defective or damaged, such as resultingfrom congenital malformation, disease, or aging. When the valve becomesdefective or damaged, the leaflets may not function properly. One commonproblem associated with a degenerating heart valve is an enlargement ofthe valve annulus (e.g., dilation). Other problems that may result invalve dysfunction are chordal elongation and lesions developing on oneor more of the leaflets.

[0003] The bicuspid or mitral valve is located in the leftatrioventricular opening of the heart for passing blood unidirectionallyfrom the left atrium to the left ventricle of the heart. The mitralvalve is encircled by a dense fibrous annular ring and includes twovalve leaflets of unequal size. A larger valve leaflet, which is knownas the anterior leaflet, is located adjacent the aortic opening. Thesmaller leaflet is the posterior leaflet.

[0004] When a mitral valve functions properly, for example, it preventsregurgitation of blood from the ventricle into the atrium when theventricle contracts. In order to withstand the substantial backpressureand prevent regurgitation of blood into the atrium during theventricular contraction, the cusps are held in place by fibrous cords(cordae tendinae) that anchor the valve cusps to the muscular wall ofthe heart.

[0005] By way of example, if an annulus enlarges or dilates to a pointwhere the attached leaflets are unable to fully close (malcoaptation),regurgitation or valve prolapse may occur. Adverse clinical symptoms,such as chest pain, cardiac arrhythmias, dyspnea, may manifest inresponse to valve prolapse or regurgitation. As a result, surgicalcorrection, either by valve repair procedures or by valve replacement,may be required.

[0006] Surgical reconstruction or repair procedures may includeplication, chordal shortening, or chordal replacement. Another commonrepair procedure relates to remodelling of the valve annulus (e.g.,annuloplasty), which may be accomplished by implantation of a prostheticring to help stabilize the annulus and to correct or help preventvalvular insufficiency which may result from defect or dysfunction ofthe valve annulus. Properly sizing and implanting the annuloplasty ringcan substantially restore the valve annulus restored to its normal,undilated, circumference. In situations where the valve leaflets exhibitlesions, it also may be necessary to reconstruct one or more valveleaflets by securing grafts or patches to the leaflets, such as overlesions or holes formed in the leaflet. The repair or reconstruction ofthe leaflets may be complicated and time consuming, the results of whichare not readily reproducible.

SUMMARY

[0007] The present invention relates to a cardiac prosthesis that may beimplanted at an annulus of a heart valve to help improve operation of adefective or damaged valve. The apparatus includes a base portion, whichmay be attached to the valve annulus for providing support at theannulus. A buttress portion extends from the base portion, such as in aradially inwardly and generally axially manner. When the apparatus isimplanted at an annulus of a heart valve, the buttress provides asurface against which one or more leaflets (depending on the type ofheart valve) may move into and out of engagement. When the leafletengages or coapts with the buttress, flow of blood through the apparatusand valve is inhibited, thereby mitigating regurgitation. The apparatusalso permits the flow of blood through the apparatus and valve as theleaflet is urged away from the buttress.

[0008] An aspect of the present invention provides an apparatus forhelping improve operation of a heart valve. The apparatus includes agenerally annular base. A buttress extends generally axially from andinwardly relative to an arc portion of the base for, when implanted,providing a surface with which a leaflet of the heart valve may moveinto and out of engagement for controlling blood flow relative to theapparatus.

[0009] Another aspect of the present invention provides an apparatus forhelping improve operation of a heart valve. The apparatus includes aframe having a generally annular base portion and a support portionextending generally axially and inwardly relative to the base portion.The support portion terminates at a distal end spaced from the baseportion. A sheath of a flexible material covers the frame to form abuttress extending between the base portion and the distal end of thesupport portion. As a result, when the apparatus is implanted, thebuttress provides a surface with which a leaflet of the heart valve maymove into and out of engagement.

[0010] To the accomplishment of the foregoing and related ends, theinvention, then, comprises the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative aspects ofthe invention. These aspects are indicative, however, of but a few ofthe various ways in which the principles of the invention may beemployed. Other objects, advantages and novel features of the inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is an isometric view of an apparatus in accordance with thepresent invention;

[0012]FIG. 2 is an outflow view of an apparatus in accordance with thepresent invention;

[0013]FIG. 3 is a side elevation of an apparatus for supporting a heartvalve in accordance with the present invention, taken along line 3-3 ofFIG. 2;

[0014]FIG. 4 is a cross-sectional view of the apparatus taken along line4-4 of FIG. 2;

[0015]FIG. 5 is an isometric view of an apparatus for supporting a heartvalve in accordance with another aspect of the present invention;

[0016]FIG. 6 is a view of the apparatus taken along line 6-6 of FIG. 5;

[0017]FIG. 7 is an isometric view of an apparatus in accordance withanother aspect of the present invention;

[0018]FIG. 8 is a cross-sectional view of the apparatus taken along line8-8 of FIG. 7;

[0019]FIG. 9 is an isometric view of a support frame for an apparatus inaccordance with another aspect of the present invention;

[0020]FIG. 10 is an isometric an apparatus in accordance with anotheraspect of the present invention, which also may be employed as a framefor an apparatus;

[0021]FIG. 11 is a cross-sectional view of part of a heart in which anapparatus, in accordance with the present invention, is mounted at aheart valve, illustrating a first condition of the heart valve; and

[0022]FIG. 12 is a cross-sectional view of the heart and apparatus,similar to FIG. 11, illustrating a second condition of the heart valve.

DESCRIPTION

[0023] FIGS. 1-4 illustrate an apparatus 10, in accordance with anaspect of the present invention, for helping improve operation of aheart valve. The apparatus 10 includes a generally annular base portion12, which may be an oval shape, egg-shaped or another suitable shapedimensioned and configured for attachment at an annulus of a heartvalve. A central axis 14 extends through the apparatus 10 substantiallytransverse to a plane extending through the base portion 12. The baseportion 12 has an inflow side 16 and an outflow side 18.

[0024] The base portion 12 may be formed of a generally rigid orflexible material, such as depending on the desired amount of supportfor a valve annulus to which the apparatus 10 is to be mounted. Forexample, the base portion 12 may be a plastic-like material, a metal, orother material suitable for implantation into a patient. The baseportion 12 provides the benefits of an annuloplasty ring (e.g., it helpssupport a valve annulus at a desired orientation at systole).

[0025] The apparatus 10 also includes a buttress 20 that is attached toand extends from the base portion 12 for providing a surface againstwhich a leaflet of a heart valve may engage. The buttress 20 isconnected to the base portion 12 along a circumferentially extending arclength of the base portion. The arc length of the base portion 12 mayapproximate the length of annular attachment for a defective or damagedvalve leaflet for which the buttress 20 (when the apparatus isimplanted) is intended to function.

[0026] By way of example, when the apparatus 10 is to be implanted atthe annulus of a mitral valve and function in place of a posteriorleaflet, the circumferential arc may approximate the length of theannulus adjacent the posterior leaflet of the valve. Additionally, thecircumferential length of the sidewall of the buttress 20 approximatesthe posterior leaflet.

[0027] The buttress 20 extends generally axially from and radiallyoutwardly relative to the outflow side 18 of the base portion 12. Anaxial length of a portion 22 of the buttress 20 proximal the baseportion 12 extends radially inwardly toward the axis 14 and generallyaxially away from the base portion. A distally extending portion 24 ofthe buttress 20 extends from the proximal portion 22 and curves radiallyoutwardly therefrom for the remaining length of the buttress toterminate in a distal end 25. The buttress 20 has a radially innersurface 26 that provides a surface against which a leaflet (e.g., ananterior leaflet of a mitral valve) may coapt at systole. As shown inFIGS. 3 and 4, a radially outer surface 28 of the buttress 20 at thedistally extending portion 24 has a generally convex or an invertedC-shaped cross-section.

[0028] In the example of the apparatus 10 shown in FIGS. 1-4 (having acomplete annular base portion 12), an aperture extends axially throughthe apparatus 10 between another arc length of the base portion 12 andthe buttress itself. The aperture provides an opening or orifice topermit the passage of blood through the apparatus 10, such as duringdiastole. The buttress 20 in conjunction with the leaflet (or leaflets)also inhibits the flow of blood when the valve is in a closed position,such as during ventricular contraction at systole.

[0029] The apparatus 10 shown in FIGS. 1-4 includes a support frame 32that is dimensioned and configured to provide a desired shape for theapparatus 10. The frame 32 provides a support mechanism that forms thebase portion 12 and the buttress 20. The frame 32, for example, may beformed of a resilient and/or flexible material, such as a plastic, metalor other material suitable for implantation into a human. The rigidityor flexibility of each part of the frame may vary depending upon theamount of support desired at the annulus (by the base portion) as wellas the amount of flexibility desired during engagement between a leafletand the buttress 20.

[0030] Alternatively, the underlying support frame 32 of the buttress 20and/or the base portion 12 may be formed of a substantiallyinelastically deformable material (e.g., it is bendable to and remainsat a desired position), such as a metal wire. As a result, a surgeonimplanting the apparatus 10 may reorient the buttress 20 and/or the baseportion 12 to a desired configuration for improving the operation of thevalve. Such material also may exhibit sufficient resilience so that itmaintains the shape set by the surgeon (or manufacturer) after beingimplanted and subjected to the dynamics of the heart valve.

[0031] The frame parts for the base portion 12 and the buttress 20 maybe formed of the same or different materials depending on the materialproperties (elasticity, rigidity, resilience, etc.) desired for eachpart of the apparatus 10.

[0032] An outer sheath 34 of a biocompatible material covers the frame32, including the base portion 12 and the buttress 20. The outer sheath34 may be substantially any material, such as a cloth-like or fabricmaterial (natural or synthetic), a biological material, such as collagenor an animal tissue material. An acceptable animal tissue material issmooth animal pericardium (e.g., equine, bovine, porcine, etc.) that hasbeen tanned or fixed in a suitable tanning environment. The pericardium,for example, is cross-linked with glutaraldehyde and undergoes adetoxification process with heparin bonding, such as one of theNO-REACT® natural tissue products that are commercially available fromShelhigh, Inc. of Millburn, N.J. The NO-REACT® natural tissue productsexhibit improved biocompatibility and mitigate calcification andthrombus formation. The exposed smooth animal pericardium covering thebuttress 20 further inhibits abrasion that could occur in response toengagement between a leaflet and the buttress.

[0033] The apparatus 10 also may include an implantation flange 36 (orsewing ring) that circumscribes the base portion of the apparatus 10.The implantation flange 36 extends radially outwardly from the baseportion 12 and provides a structure for facilitating implantation of theapparatus 10 at an annulus of a heart valve. The implantation flange 36is formed of a flexible material, such a cloth-like or fabric material(natural or synthetic), a biological material, such as collagen, or ananimal tissue material. For example, the implantation flange 36 isformed of a substantially biocompatible biological material, such asanimal tissue (e.g., animal pericardium). The implantation flange 36 maybe formed as an integral part of the outer sheath 34, such as a singleor double layer of the material that is used to form the outer sheath.

[0034]FIGS. 5 and 6 illustrate a heart valve repair apparatus 150 inaccordance with another aspect of the present invention. The apparatus150 includes a generally annular base portion 152 that is generallyC-shaped (or incomplete). The base portion 152 has ends 156 and 158 thatare spaced apart from each other and a curved portion extending betweenthe ends. In this example, the base portion 152 includes an underlyingC-shaped support ring, which may be formed of a flexible, resilient, orgenerally rigid material. The support ring may have an elastic propertyso as to return to its original shape when deflected from its original(or rest) condition. The support ring for example, may be a plastic-likematerial (e.g., a polymer, a resin, etc.) or a metal (e.g., stainlesssteel), such as in the form of a wire. It will be understood andappreciated that other types of generally rigid, elastic, and/orresilient materials also may be used in accordance with the presentinvention. In addition, a suitable inelastically deformable materialalso could be used to form the support ring.

[0035] A buttress 164 extends generally axially from an outflow side 166of the base portion 152 in a manner that is substantially similar tothat shown and described with respect to FIGS. 1-4. Briefly stated, aproximal portion 168 of the buttress 164 extends generally axially andradially inward from the base portion 152 toward an open end (betweenends 156 and 158) of the base portion. A distally extending portion 170of the buttress 164 extends from the proximal portion 168 and curvesradially outwardly therefrom for the remaining length of the buttress.The buttress 164 has a radially inner surface 172 that provides asurface against which a leaflet (e.g., an anterior leaflet of a mitralvalve) may coapt at systole. The buttress 164 is dimensioned andconfigured to simulate the dimensions and configuration of a leaflet atsystole so that, when the apparatus 150 is implanted at an annulus of aheart valve, a leaflet (or leaflets) may engage the buttress 164 toclose the valve at systole. The leaflet (or leaflets) is able to coaptwith the inner surface 172 of the buttress 164 at systole, therebyinhibiting regurgitation of blood when the ventricle contracts.

[0036] As in the example of FIGS. 1-4, the apparatus 150 also includesan outer sheath 174 of a flexible, biocompatible material covering theapparatus. The apparatus 150 also may include an implantation flange 176(or sewing ring) that circumscribes the baseportion 152 of theapparatus. The implantation flange 176 extends radially outwardly fromthe base portion 12 between the ends 156 and 158 for facilitatingimplantation of the apparatus 150 at an annulus of a heart valve. Eachof the outer sheath 174 and the implantation flange 176 may be formed ofany suitable flexible, biocompatible material, such as a cloth-like orfabric (natural or synthetic) material, a biological material, such ascollagen or an animal tissue material. An acceptable animal tissuematerial is smooth animal pericardium (e.g., equine, bovine, porcine,etc.), such as a NO-REACT® tissue product.

[0037]FIGS. 7 and 8 illustrate a heart valve repair apparatus 200 inaccordance with another aspect of the present invention. The apparatus200 includes a generally annular base portion 202. The base portion 202includes a support ring 203 that is dimensioned and configured toapproximate the dimensions and configuration of a heart valve annulus,such as a mitral or atrioventricular valve. The support ring 203 may besubstantially similar to that disclosed with respect to the baseportions shown and described with respect to FIGS. 1-6 (e.g., it may bea complete ring (as shown) or a generally C-shaped ring).

[0038] A pair of support posts 204 and 206 extend generally axially froman outflow side 208 of the base portion 202. The supports 204 and 206are circumferentially spaced apart from each other an arc length thatapproximates the circumferential dimension of a valve leaflet for whichthe apparatus 200 is intended to function. The support posts 204 and 206may be formed of the same material or a different material as that whichforms the base portion 202. For example, the support posts 204 and 206and the base portion 202 may be formed as an integral unit in a suitableinjection molding process. It is to be appreciated, however, thatdifferent materials also may be utilized to form the supports 204 and206 and the base portion 202, with the supports being appropriatelysecured to the base portion, such as by ultrasonic welding or anothermethod of attachment.

[0039] The apparatus 200 also includes a buttress 210 of a substantiallyflexible material that extends generally axially from the base portion202 for providing a flexible surface for abutment with an adjacentleaflet of a heart valve. The buttress 210, for example, includes aflexible sheet 212 of material that is attached to the base portion 202along a circumferentially extending arc 214 between the juncture of eachof the support posts 204 and 206 and the base portion. The flexiblesheet 212 of material extends generally axially from the base portion202 and is connected to and extends between the support posts 204 and206. The support posts 204 and 206 may be linear or curved to orient thesheath of flexible material connected therebetween at a desired positionfor engaging an adjacent leaflet. The sheet 212 of flexible materialalso may cover each of the support posts 204 and 206 as well as theannular base portion 202 so as to completely cover the frame, which isformed of the base portion and support posts. The sheet 212 of flexiblematerial of the buttress 210 provides a radially inner surface 216 withwhich an adjacent leaflet may move into and out of engagement when theapparatus 200 is implanted. The flexible sheath 212 of material also maypermit flexible movement of the buttress 210 relative to the supports204 and 206, such that when the apparatus is implanted it facilitatescoaptation between an adjacent leaflet (or leaflets) and the buttress.

[0040] As mentioned above with respect to the apparatus of FIGS. 1-4,the posts 204 and 206 and/or the base portion 202 may be formed of aninelastically deformable material. A surgeon implanting the apparatus200, thus, may bend the buttress 210 and/or base portion 202 to adesired configuration. As a result, each apparatus may be customized fora patient so as to improve the operation of a heart valve when theapparatus 200 is implanted at the valve annulus.

[0041] The sheet 212 of flexible material, for example, may be a clothor fabric material (natural or synthetic), a biological material, suchas a sheet of collagen material or an animal tissue material, such asanimal pericardium. In order to inhibit regurgitation of blood whenimplanted at a heart valve, the flexible sheath 212 of material shouldbe substantially impervious to the flow of blood therethrough.

[0042] As illustrated in FIGS. 7 and 8, the apparatus also may includean implantation flange (or sewing ring) 220 for facilitatingimplantation of the apparatus at an annulus of a heart valve. Theimplantation flange 220 extends radially outwardly from the base portion202. The implantation flange 220 is formed of a flexible material, sucha cloth-like or fabric material (natural or synthetic), or a biologicalmaterial, such as collagen or an animal tissue material. For example,the implantation flange 220 is formed of a biocompatible biologicalmaterial, such as animal tissue (e.g., animal pericardium), which is thesame material that forms the outer sheath 212.

[0043]FIG. 9 illustrates a frame 250 that may be employed to form anapparatus for helping repair a heart valve in accordance with anotheraspect of the present invention. For example, the frame 250 may be usedto form an apparatus of a type similar to that shown and described withrespect to. FIGS. 1-4. The frame 250 provides a skeleton over which anouter sheath of a substantially flexible material may be applied.

[0044] The frame 250 includes a generally annular base portion 252.While the base portion 252 is illustrated as a complete ring, it will beunderstood and appreciated by those skilled in the art that anincomplete ring (e.g., a C-shaped ring) alternatively may be utilized inaccordance with an aspect of the present invention. The base portion 252includes an inflow side 254, and outflow side 256, with a central axis258 extending through the base portion.

[0045] The frame 250 also includes a support 260 extending generallyaxially from the base portion 252. The axially extending support 260 isin the form of a curved structure that connects substantially opposededges 262 and 264 of the base portion 252 for providing a supportstructure for a buttress.

[0046] The frame 250, for example, may be formed of a resilientmaterial, a flexible material, or an inelastically deformable material,such as a plastic, a metal, or other material suitable for implantationinto a human. The rigidity or flexibility of a material utilized to formthe frame 250 may vary depending upon the amount of support desired atthe annulus (by the base portion) as well as the amount of flexibilitydesired during coaptation between a leaflet and the buttress. The baseportion 252 and the axially extending support 260 may be formed of thesame or different materials, depending on the material properties(elasticity, rigidity, resilience, etc.) desired for each part of theframe 250.

[0047] The frame 250 may be covered with a sheet of a substantiallyflexible material to form an apparatus, similar to that shown anddescribed with respect to FIGS. 1-4. A sheet of flexible material isapplied over the frame so that the flexible material may be moveablerelative to the axially extending support 260, such as in response to anadjacent leaflet moving into engagement with the overlying sheet ofmaterial. In contrast, the illustrated apparatus of FIGS. 1-4 employs aframe that includes a substrate material coextensive with the buttressonto which the sheet of flexible material is applied (e.g., the buttressof FIGS. 1-4 may be more static than the flexible buttress of FIG. 9).

[0048]FIG. 10 illustrates a heart valve repair apparatus 280 inaccordance with another aspect of the present invention. Similar to theapparatus 10 of FIG. 1, the apparatus 280 includes a generally annularbase portion 282 that is dimensioned and configured according to thedimensions and configuration of a heart valve annulus to which theapparatus is to be attached. As mentioned above with respect to FIGS.1-4, the flexibility or resilience or rigidity of the base portion 282may vary according to the material used to form the base portion, suchas to provide a desired amount of support at the heart valve annulus.

[0049] A buttress 284 is attached to and extends radially inwardly andgenerally axially away from a posterior arc 286 of the base portion 282.More specifically, a proximal portion 288 of the buttress 284 extendsaxially and radially inwardly over a first portion of its length. Aremaining portion 290 of the buttress 284 extends distally from theproximal portion 288 and curves radially outwardly relative to (or awayfrom) the proximal portion. When the apparatus 280 is implanted, thebuttress 284 provides a surface with which an adjacent leaflet may moveinto and out of engagement.

[0050] The apparatus 280 may be formed of a flexible and/or resilientmaterial, such as a polymer or plastic-like material (e.g., Delrin®),pyrolythic carbon, etc.), a metal, or other material consideredappropriate for implantation into a heart. The base portion 282 and thebuttress 284, for example, may be formed of the same material to form anintegral apparatus. Alternatively, different materials may be utilizedto form each of the buttress 284 and the base portion 282, such as whendifferent amounts of rigidity or flexibility may be desired for eachrespective part.

[0051] It will be understood and appreciated that the apparatus 280further may be employed as the underlying frame 32 of the apparatus 10,as shown and described with respect to FIGS. 1-4. In order to form theapparatus 10 from the apparatus 280, an outer sheath of an appropriateflexible, biocompatible material is mounted over the apparatus 280, suchas set forth above.

[0052]FIGS. 11 and 12 illustrate part of a heart 300 in which anapparatus, such as the apparatus 10 illustrated with respect to FIGS.1-4, is implanted at an annulus 302 of a mitral valve 303. The mitralvalve 303 is intended to provide for the unidirectional flow of bloodfrom the left atrium 304 into the left ventricle 306. The mitral valve303 includes an anterior leaflet 308 that extends from the annulus 300adjacent the aortic opening 310 and attaches to the muscular tissue inthe wall of the left ventricle by fibrous cordae tendinae 312. Theposterior leaflet has been substantially removed from the heart, such asby excising it prior to implantation of the apparatus 10. It is to beunderstood and appreciated, however, that the posterior leaflet mayremain intact, with a buttress 20 of the apparatus 10 interposed betweenthe posterior and anterior leaflets.

[0053] As mentioned above, the apparatus 10 may include an implantationflange 36 that is sutured to the fibrous tissue at the annulus 302 ofthe valve 303. The buttress 20 extends from the base 12 of the apparatus10 into the ventricle 306 at a position corresponding to the position ofthe posterior leaflet of the mitral valve 303. As mentioned above, thebuttress 20 extends into the ventricle 306 generally toward theposterior leaflet 308.

[0054] It is to be appreciated that the buttress 20 may be formed of agenerally rigid material that remains substantially stationary (e.g.,static) during both systole and diastole. Alternatively, the buttress 20may sufficiently flexible material, such as a sheet of materialsupported in a peripheral frame (see, e.g., FIGS. 7-9) or by employing amore flexible type of frame to permit movement thereof commensurate withthe flow of blood from the atrium 304 into the ventricle 306 through thevalve 303.

[0055]FIG. 11 illustrates the mitral valve 303 is in a closed position(at systole), in which the anterior leaflet 304 engages the buttress 20of the apparatus 10 in accordance with an aspect of the presentinvention. That is, the buttress 20 of the apparatus 10 simulates thefunction of the posterior leaflet at systole by providing a surfaceagainst which the anterior leaflet 308 coapts. As a result, the buttress20 and the anterior leaflet 304 cooperate to inhibit regurgitation ofblood from the left ventricle 308 into the left atrium 306, such asduring ventricular contraction at systole.

[0056] The buttress 20 in conjunction with the anterior leaflet alsofacilitates and promotes unidirectional flow of blood at diastole, suchas shown in FIG. 11 by arrow 314. In particular, an opening or apertureextends through the implanted apparatus 10 between the buttress 20 andthe anterior leaflet 308. Advantageously, the movement of the anteriorleaflet 308 relative to the buttress 20, in response to the flow ofblood during diastole, provides a sufficient orifice to permit the freeflow the flow of blood from the left atrium 304 into the left ventricle306. The buttress 20 also may be formed of a flexible material that isable to move radially relative to the base portion 12 to furtherfacilitate blood flow. The annular base portion 12 of the apparatus 10also may help support the annulus 302 of the mitral valve 303 at systoleto promote the desired coaptation between the buttress 20 and theanterior leaflet 308 (FIG. 10).

[0057] In view of the foregoing, an apparatus according to the presentinvention provides a useful repair apparatus for helping to improveoperation of a heart valve. The apparatus may be employed to bothsupport a heart valve annulus and mitigate problems associated withcoaptation and/or lesions in a leaflet by providing a buttress withwhich one or more leaflets may move into and out of engagement. Theapparatus further provides a simplified repair option (implanting adevice at an annulus of a heart valve) when compared with other, moreconventional methods of reconstruction and repair.

[0058] It is to be appreciated by those skilled in the art that, whilethe illustrated examples show the apparatus for treating a bicuspid(mitral) valve, an apparatus in accordance with the present inventionalso may be used for repairing other types of heart valves (e.g., atricuspid valve or other bicuspid valves). In addition, an apparatus mayin accordance with the present invention, be implanted at either theinflow side or outflow side of a heart valve annulus.

[0059] What has been described above are examples of the presentinvention. It is, of course, not possible to describe every conceivablecombination of components or methodologies for purposes of describingthe present invention, but one of ordinary skill in the art willrecognize that many further combinations and permutations of the presentinvention are possible. Accordingly, the present invention is intendedto embrace all such alterations, modifications and variations that fallwithin the spirit and scope of the appended claims. Furthermore, to theextent that the term “includes” is used in either the detaileddescription or the claims, such term is intended to be inclusive in amanner similar to the term “comprising.”

What is claimed is:
 1. An apparatus for helping improve operation of aheart valve, comprising: a generally annular base portion; and abuttress extending generally axially from and inwardly relative to aportion of the base for, when the apparatus is implanted, providing asurface with which a leaflet of the heart valve may move into and out ofengagement for controlling blood flow relative to the apparatus.
 2. Anapparatus as set forth in claim 1, wherein the generally annular baseportion is a generally C-shaped base portion having a curved lengthbetween opposed ends of the C-shaped base portion, the buttressextending from an arc portion of the C-shaped base portion intermediatethe opposed ends thereof.
 3. An apparatus as set forth in claim 2,wherein the buttress extends a first length in a direction radiallyinwardly and axially from the base portion and then curves outwardly fora second length thereof.
 4. An apparatus as set forth in claim 1,wherein the annular base portion is a complete ring and an apertureextends through the apparatus between the buttress and an opposed sideof the annular base portion.
 5. An apparatus as set forth in claim 1,wherein the base portion is formed of a generally rigid material.
 6. Anapparatus as set forth in claim 1, wherein the base portion is formed ofa substantially flexible material.
 7. An apparatus as set forth in claim1, further including an outer sheath of a substantially flexiblematerial covering the surface of the buttress.
 8. An apparatus as setforth in claim 7, wherein the outer sheath completely covers thebuttress and the base portion.
 9. An apparatus as set forth in claim 8,wherein the flexible material is a substantially biocompatible animaltissue material.
 10. An apparatus as set forth in claim 9, wherein thebiocompatible animal tissue material is animal pericardium.
 11. Anapparatus as set forth in claim 1, further including an implantationflange circumscribing the base portion.
 12. An apparatus as set forth inclaim 11, wherein the implantation flange is formed of a substantiallyflexible material.
 13. An apparatus as set forth in claim 12, whereinthe implantation flange is formed of a substantially biocompatibleanimal tissue material.
 14. An apparatus as set forth in claim 13,wherein the animal tissue material is animal pericardium.
 15. Anapparatus as set forth in claim 1, further including two elongated postsextending generally axially from the annular base portion for supportinga sheet of flexible material that forms the surface of the buttress, thesheet of flexible material extending from a circumferential arc of thebase portion and connecting to each of the two posts.
 16. An apparatusas set forth in claim 15, wherein the posts are formed of a generallyrigid material.
 17. An apparatus as set forth in claim 16, wherein thesheet of flexible material is a substantially biocompatible animaltissue material.
 18. An apparatus as set forth in claim 15, wherein eachof the posts extend from the base portion and terminate in respectivedistal ends, the apparatus further including an interconnecting supportportion connecting the distal ends of the posts.
 19. An apparatus forhelping improve operation of a heart valve, comprising: a framecomprising a generally annular base portion and a support portionextending generally axially and inwardly relative to the base portion,the support portion terminating at a distal end spaced from the baseportion; and a sheath of a substantially flexible material extendingfrom an arc of the base portion and to the support portion of the framenear the distal end thereof to form a buttress which, when the apparatusis implanted, provides a surface with which a leaflet of the heart valvemay move into and out of engagement.
 20. An apparatus as set forth inclaim 19, wherein the generally annular base portion is a generallyC-shaped base portion having a curved length between opposed ends of theC-shaped base portion, the buttress extending from an arc portion of theC-shaped base portion intermediate the opposed ends thereof.
 21. Anapparatus as set forth in claim 19, wherein the support portion of theframe extends a first length in a direction radially inwardly andaxially from the base portion and then curves outwardly for a secondlength thereof, the sheath of flexible material substantially conformingthe shape of the frame.
 22. An apparatus as set forth in claim 19,wherein the annular base portion is a complete ring and an apertureextends through the apparatus between the buttress and an opposed sideof the annular base portion.
 23. An apparatus as set forth in claim 19,wherein the sheath of flexible material is a substantially biocompatibleanimal tissue.
 24. An apparatus as set forth in claim 23, wherein thebiocompatible animal tissue is animal pericardium.
 25. An apparatus asset forth in claim 19, further including an implantation flangecircumscribing at least a substantial part of the base portion.
 26. Anapparatus as set forth in claim 19, wherein the support portion of theframe further includes two elongated posts extending generally axiallyfrom the annular base portion for supporting the sheath of flexiblematerial extending between the posts to form the surface of thebuttress.
 27. An apparatus as set forth in claim 26, wherein the postsare formed of a generally rigid material.
 28. An apparatus as set forthin claim 26, wherein each of the two posts extend from the base portionand terminate in distal ends, the support portion of the frame furtherincluding an interconnecting member connecting the distal ends of theposts.
 29. An apparatus for helping improve operation of a heart valve,comprising: support means for attaching at an annulus of the heart valveso as to permit blood flow through the support means; and buttress meansextending from the support means for, when the apparatus is attached atthe annulus, providing a surface with which a leaflet of the valve maymove into and out of engagement for controlling blood flow relative tothe apparatus.